BURLINGTON — Police say a muddy check torn into pieces and sent to the IRS in Burlington caused a hazardous-materials scare that led to the evacuation of more than 100 office workers.

The IRS reported the check’s arrival to police at about 10:30 a.m. Thursday. The Lakeside Avenue building was evacuated and police declared it was safe about three hours later.

Police said someone found a mud-covered check, ripped it to pieces and sent it to the IRS. But when the letter arrived, the mud had dried, crumbled to the bottom of the envelope and formed a granular substance, causing some alarm.

Numerous businesses also have offices inside the building, known as the Innovation Center.